Abstract Many young adults with type 1 diabetes (T1D) struggle with the complex daily demands of adherence to their medical regimen and fail to achieve good glycemic control. However, few interventions have been developed specifically for this age group. In the proposed study, we will provide an app (SweetGoals) to all participants as a ?core? intervention. The app prompts participants to upload their diabetes devices weekly to a device-agnostic uploader (Glooko), will automatically retrieve uploaded data and apply decision rules about daily and weekly self-management goals, and will generate feedback messages about goal attainment. Further, the proposed study will test two unique intervention components designed to support and optimize digital self-monitoring, goal setting, and goal achievement. These components include (1) incentives to promote consistent daily adherence to goals, and (2) web health coaching to teach effective problem solving focused on personalized barriers to self-management. We will use a novel digital direct-to-patient recruitment method and intervention delivery model that transcends the clinic. Instead of relying on the clinic to transform its system of care, our intervention will directly assist young adult patients in developing skills to improve their utilization of the health care system. A prior pilot RCT (N=61) comparing this intervention approach to usual care among adolescents showed significant and sustained impact on A1c. These results were very promising, and we believe this intervention is well suited to young adults. In the proposed study, 300 young adults ages 19-25 with T1D and above target (Hb)A1c (? 8.0%) will be recruited via social media. All participants will receive the SweetGoals app built on an open-source intervention platform MobileCoach (www.Mobile- Coach.eu). The app automates many features of our piloted intervention, greatly increasing disseminability. These include automatic retrieval of diabetes device data ?digested? by Glooko and prompting and providing feedback on adherence goals. Adherence targets include (a) daily glucose monitoring; and (b) mealtime behaviors. A 22 factorial design will be used to test the main and interactive effects of (1) modest financial incentives for meeting adherence targets and (2) web health coaching. Coaches will teach a problem-solving approach that generates personalized solutions to adherence challenges. The intervention will last 6 months. The primary outcome will be reduction in A1c. We hypothesize greater sustained A1c improvements in participants who receive coaching and who receive incentives. Further, we hypothesize a synergistic interaction between these components, resulting in greater positive outcomes among those receiving both. We will also test four key self-regulation mechanisms and app engagement metrics as predictors of outcomes. Successful completion of these aims will support dissemination and effectiveness studies of this intervention that seeks to improve glycemic control in this high-risk and understudied population of young adults with T1D.